This invention relates to a bolt for a truss to be used when plural pipes for structural purposes are connected to a member for constructing a truss.
As shown in FIG. 6, a conventional bolt for a truss to be used when plural pipes for structural purposes are connected to a member used in the construction of the truss, comprises a main body 21 in which a threaded shaft portion 24 is formed at the end of a shaft portion 23. A head portion 22 is formed at the other end thereof and a pin hole 20 is pierced in the middle of the shaft portion 23; a polygonal tube 26 having a slotted hole 28 in a body thereof is slidably engaged with the shaft portion 23; and a pin 25 connects the polygonal tube 26 to the shaft portion 23. When a pipe 31 for structural purposes is connected to a member 27 for constructing a truss, a sleeve 32 welded to the end of the pipe 31 for structural purposes is engaged with a lower collar portion of the shaft portion 23; the polygonal tube 26 is engaged from the shaft end of the shaft portion 23; the pin 25 is inserted into the pin hole 20 through the slotted hole 28; and then the polygonal tube 26 is rotated, whereby the main body 21 is rotated to insert the threaded shaft portion 24 into a tapped hole 29 of the member 27 for constructing a truss by screwing.
Since the polygonal tube 26 and the main body 21 are slidably connected by restricting rotation by the pin 25, the pin hole 20 of the shaft portion 23 and the slotted hole 28 of the polygonal tube 26 are required, whereby there are problems that mechanical strength of the main body 21 and the polygonal tube 26 is lowered and corrosion resistance is also lowered by a drilling and there is a problem of an increase in cost caused by a step of a drilling.